Inequalities in geographic barriers and patient representation in lymphoma clinical trials across England

The distribution of trial site locations may lead to disparities in geographic access and affect patient representativeness in clinical trials. We utilised trial data covering 1993-2022 from the National Institute for Health and Care Research (NIHR) Open Data Platform, 2011 and 2021 English Census and geographic data and English individual-patient cancer registry data for patients diagnosed with lymphoma between 1997 and 2017. To assess representation, we compared patient age and sex between trial participants and the incident population. We mapped the distance and travel times of English lower layer super output areas (LSOAs) to their nearest research active NHS Trusts and assessed associations between distance and travel times and the geographic and sociodemographic characteristics of the LSOAs. Trial participants were younger than the incident population and more likely to be male. The closest NHS Trust to more than half of English LSOAs was not research active. Greater LSOA mean age, male percent, White British percent, rurality and coastal/border status were positively associated with distance and travel time (at prespecified p < 0.05 level), while greater deprivation was negatively associated. Female and older lymphoma patients in England are underrepresented in trials, with the latter facing a higher burden of geographic barriers.